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It takes Ann, brad and chad two hours to paint a fence. When Ann works alone , she can paint the same fence in six hours. When brad works alone , he can paint the same fence in four hours. How long would it take for chad to paint the same fence on his own

 Apr 20, 2020
 #1
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1/a  + 1/b  + 1/c = 1/2

1/6  +  1/4 + 1/c  = 1/2       solve for 'c' the time of chad alone

2/12  + 3/12  + 1/c = 1/2

1/c  =  1/2 - 5/12

1/c = 1/12

c = 12 hours

 Apr 20, 2020

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